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Cell and Tissue Research

, Volume 368, Issue 3, pp 615–627 | Cite as

Comprehensive functional analysis of Rab GTPases in Drosophila nephrocytes

  • Yulong Fu
  • Jun-yi Zhu
  • Fujian Zhang
  • Adam Richman
  • Zhanzheng Zhao
  • Zhe HanEmail author
Regular Article

Abstract

The Drosophila nephrocyte is a critical component of the fly renal system and bears structural and functional homology to podocytes and proximal tubule cells of the mammalian kidney. Investigations of nephrocyte cell biological processes are fundamental to understanding the insect renal system. Nephrocytes are highly active in endocytosis and vesicle trafficking. Rab GTPases regulate endocytosis and trafficking but specific functions of nephrocyte Rabs remain undefined. We analyzed Rab GTPase expression and function in Drosophila nephrocytes and found that 11 out of 27 Drosophila Rabs were required for normal activity. Rabs 1, 5, 7, 11 and 35 were most important. Gene silencing of the nephrocyte-specific Rab5 eliminated all intracellular vesicles and the specialized plasma membrane structures essential for nephrocyte function. Rab7 silencing dramatically increased clear vacuoles and reduced lysosomes. Rab11 silencing increased lysosomes and reduced clear vacuoles. Our results suggest that Rab5 mediates endocytosis that is essential for the maintenance of functionally critical nephrocyte plasma membrane structures and that Rabs 7 and 11 mediate alternative downstream vesicle trafficking pathways leading to protein degradation and membrane recycling, respectively. Elucidating molecular pathways underlying nephrocyte function has the potential to yield important insights into human kidney cell physiology and mechanisms of cell injury that lead to disease. The Drosophila nephrocyte is emerging as a useful in vivo model system for molecular target identification and initial testing of therapeutic approaches in humans.

Keywords

Drosophila Nephrocyte Rab Vesicle trafficking Endosome 

Notes

Acknowledgements

We thank the Bloomington Drosophila Stock Center and the VDRC for Drosophila stocks. We acknowledge the Microscopy and Image Analysis Laboratory at the University of Michigan for their technical support with transmission electron microscopy. We are especially grateful to Dotty Sorenson and Sasha Meshinchi for their assistance in electron microscopy. Z.H. was supported by grant R01-DK098410 from the NIH.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

441_2017_2575_MOESM1_ESM.pdf (56 kb)
ESM 1 (PDF 55 kb)

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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Yulong Fu
    • 1
  • Jun-yi Zhu
    • 1
  • Fujian Zhang
    • 2
  • Adam Richman
    • 1
  • Zhanzheng Zhao
    • 3
  • Zhe Han
    • 1
    Email author
  1. 1.Center for Cancer and Immunology ResearchChildren’s Research Institute, Children’s National Medical CenterWashingtonUSA
  2. 2.Division of Nephrology, Nanfang HospitalSouthern Medical UniversityGuangzhouPeople’s Republic of China
  3. 3.Department of NephrologyFirst Affiliated Hospital of Zhengzhou UniversityZhengzhouPeople’s Republic of China

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